This application claims priority to Application No. EP 01103318.0 which was published in the English language on Feb. 13, 2001.
The invention relates to a method for an automotive vehicle to display a road map, and in particular, to display a road map that features an instantaneous signal of the actual vehicle orientation and position while maintaining the orientation and position on a long term basis steady with respect to a display field.
Standard vehicle navigation systems typically include an arrangement for a map that will display various aspects of a planned route, such as a complete or partial road network in a region around the actual position of the vehicle. These same systems typically highlight the route that is to be followed according to the planning by the system. An elementary display system will display the map in a stationary manner, for example, indication north in the xe2x80x9cupxe2x80x9d direction. A more advanced system may include a dynamic display, wherein the direction instantaneously followed by the vehicle will always be in the xe2x80x9cupxe2x80x9d direction.
Under normal driving conditions the display of the vehicle in the xe2x80x9cupxe2x80x9d direction will cause far too many rotations of the map. This will even apply when a certain averaging is effected of the instantaneous curves that are being followed. In the case of the vehicle following a route that is partially curved, but on the whole more or less straight, many of the rotations are superfluous and distracting to the driver. The above problem will likewise occur when the route being followed is displayed, without a route planning feature being present or active.
The present invention seeks to restrict the amount and/or number of rotations in displaying a map to prevent distracting the driver and or detracting his attention from other incidents that could warrant immediate action.
According to one embodiment of the invention, there is a method for setting up a geographical window regarding actual movements of the vehicle, and checking whether the vehicle remains inside or outside the window. If the vehicle remains inside the window, displaying the movements while at least partially suppressing the orientation. If outside the window, displaying the movements while substantially upholding the orientation. Such will allow for a more pleasant display mode that will nevertheless present a user with adequate and easy-to-understand information regarding the vehicle position, and as such will improve the ergonomic performance of the display subsystem.
In a preferred embodiment of the invention, the window has a first angular size. Small changes in the orientation or heading of the vehicle will cause little necessity for changing the display.
In another preferred embodiment of the invention, the window has a first smaller angular size wherein maintaining the orientation is fully suppressed, and a second larger angular size wherein maintaining the orientation is temporarily attenuated. Such temporarily attenuating may imply a low-pass filtering of the changes, or generally, various operations to be executed in the time domain.
Alternatively, the temporarily attenuating may imply a full suppressing of the angular change during a predetermined period of time, but thereafter allowing a filtered change of the map orientation.
Advantageously, such window has a first linear size. Small movements in the position of the vehicle will cause little necessity for changing the display.
Preferably, such window has a first smaller linear size wherein maintaining the position is fully suppressed, and a second larger angular size wherein maintaining the position is temporarily attenuated. Such temporarily attenuating may again imply a low-pass filtering of the changes, or generally, various operations to be executed in the time domain. Again, the temporary attenuating may alternatively imply a full suppressing of the linear change during a predetermined period of time, but thereafter allowing a filtered change of the map position.
In another preferred embodiment of the invention, the method includes determining long-term values for shift and rotation of the vehicle position with respect to a geography, effecting such maintaining with respect to such long-term values, while suppressing the maintaining with respect to discrepancies between actual vehicle position and orientation with respect to such long-term values. This invention will under various circumstances produce a computationally and/or ergonomically superior solution.
Another embodiment of the invention relates to a vehicle route display system arranged for implementing a method for displaying, in an automotive vehicle, a road map including actual vehicle orientation and position which on a long term basis are maintained steady and on a short time basis selectively maintained under control of checking vehicle movements versus a window, and to a vehicle provided with such route display system.